At its January 27, 2026 general meeting, the Gowanus Canal Community Advisory Group passed the following resolution asking the New York State Department of Environmental Conservation (NYSDEC) to amend the Class SC rule to maintain the previous dissolved oxygen standard of no less than 4.0 mg/L that had been in place under the Class I designation for the Gowanus Canal.
Effective on October 15, 2025, NYSDEC amended key water quality classifications, including reclassifying the Gowanus Canal to Class SC (swimmable and fishable). This reclassification inadvertently lowered the standards for dissolved oxygen levels in the Canal.
The resolution reads as follows:
Background
On October 15, 2025, the NYSDEC issued a Notice of Adoption (NOA) in the State Register, adopting updates to water quality classifications, including amendments to the classification of the Gowanus Canal. Please consider this resolution in response to the reclassification of the Gowanus Canal to Class SC (swimmable and fishable).
Petition & Comments
Effective October 15, 2025, NYSDEC amended key water quality classifications, including reclassifying the Canal to Class SC (swimmable and fishable). Previously, the Gowanus Canal had been classified as Class SD (fishable only) in the upper section, upstream of the Gowanus Expressway, and Class I (fishable only) in the lower section, downstream of the Gowanus Expressway. The CAG submits this resolution in response to DEC’s decision to reclassify the Gowanus Canal and encourages DEC to expedite an amendment to the SC regulations to require the higher DO levels that were previously required in the Canal.
The CAG has long advocated for reclassification of the Canal to better reflect the area’s current conditions and anticipated future uses. The CAG appreciates DEC’s decision to reclassify the Canal to Class SC, as the CAG previously petitioned. This designation represents an important and meaningful step forward and reflects a history of persistent community advocacy for improved water quality in the Canal.
However, the CAG is concerned that this reclassification inadvertently lowered the standards for dissolved oxygen (DO) levels in parts of the canal, an apparent unintended consequence of the reclassification. Under 6 CRR-NY 703.3 Water quality standards for pH, dissolved oxygen, dissolved solids, odor, color and turbidity, the DO concentration is not permitted to fall below 4.0 mg/L at any time for Class I waterbodies. In contrast, the DO concentration is not allowed to be less than 3.0 mg/L at any time for Class SC waterbodies.
As a result, under the Class SC designation, parts of the Canal are now subject to a less protective DO standard than was previously required.
Adequate DO levels are essential to sustain aquatic life, including plants, animals, and fish. The importance of maintaining sufficient DO levels in the Canal is underscored by recent events. In July 2023, the Canal experienced a large-scale fish kill, with thousands of dead fish observed floating on the surface. This mass fish die-off was the result of dangerously low levels of DO that caused widespread asphyxiation of the fish in the Canal. Allowing lower DO standards increases the risk of similar events and threatens the progress that has been made toward supporting aquatic life in the Canal.
Because the reclassification of the Canal to Class SC carries lower requirements for the DO concentration than the previous classification, the CAG strongly urges DEC to amend the Class SC rule to maintain the previous DO standard of no less than 4.0 mg/L that had been in place under the Class I designation.
Given the CAG’s current understanding of these requirements under the waterbody classifications, the CAG contends that it is essential that DO standards in the Canal not be weakened as a result of the otherwise welcome reclassification to SC. Protective water quality standards, once established, should not be reduced through changes in classification. Maintaining the higher DO requirement is critical to supporting aquatic life and safeguarding existing water quality standards. The CAG remains committed to the restoration and long-term protection of the Canal in accordance with federal and state law, and looks forward to continued collaboration with DEC to ensure that water quality standards reflect the priorities and needs of the community and Canal.